Study On Decolorization Process And Mechanism Advanced Treatment Of Vitamin C Wastewater

The chrominance of vitamin C wastewater is very high, and theingredient of it is very complex, it contains a lot of organic matter that arevery difficult to be degraded. Now, the anaerobic-aerobic biological methodswere wildly used for treating vitamin C wastewater at home and abroad.After anaerobic-aerobic biological treatment, chrominance of the wastewaterhas got a large degree removal, nevertheless, it is still brown yellow thatgeneral can satisfy “Integrated wastewater discharge standard”(GB8978-1996). With the increase of the state environmental protectionefforts, in2008, the state environmental protection administration hadestablished “Discharge standard of water pollutant for pharmaceuticalindustry Fermentation products category”(GB21903-2008). It has higherstandard for chrominance of the wastewater. Therefore, it is very necessaryfor vitamin C wastewater to do the advanced treatment.Study on decolorization process and mechanism advanced treatment ofthe effluent from anaerobic-aerobic biological treatment of vitamin C wastewater, Combining single-factor experiment and the practicalcharacteristics of the project, research the optimal operation conditions of allprocessing unit, and then by compare treatment effect of the same processingunit, such as pretreatment unit、biological treatment unit, finally got the bestcombination decolorization process, at the same time, preliminary discussionof chromogenic mechanism of vitamin C wastewater by Ultraviolet-visiblespectrum and Infrared spectrum has been done．Through the research of the advanced treatment of vitamin C wastewater,some conclusions had been gotten.First, got the optimal operation conditions of all processing unit, and bycompare, finally got the best combination decolorization process.Second, after treated by the best combination decolorization process, theTOC of effluents fell from96.0～148.0mg/L to16.2～23.3mg/L, more than84.1%of TOC was removed，the chrominance of effluents fell from250～380times low to19～30times, more than91.7%of chrominance wasremoved, discharge met the standards of water pollutant (GB21903-2008) forfermentation pharmaceutical industry. In this process, the average TOC and chrominance removal efficiency of catalytic ozonation are38.3%and50.1%;the average TOC and chrominance removal efficiency of integrated reactorare32.0%and35.1%; the average TOC and chrominance removal efficiencyof disinfectant pool are59.7%and79.2%, and we can found catalyticozonation for the chrominance removal of wastewater has the best efficiency.Third, from the Ultraviolet-visible spectrum, we can deduce that somechromophores such as carbonyl compound and ester maybe in vitamin Cwastewater. After treated by the best decolorization process, the absorbanceduring the visible and ultraviolet decreased significantly, while thechrominance of vitamin C wastewater has also been a large extent of removal.It is indicating that the refractory organic matter is a major contributor to thechrominance of wastewater. From the Infrared spectrum, we can deduce thatthe chrominance was mainly from the carbonyl groups and R-O-Cauxochrome organic matter in vitamin C wastewater. After treated bycatalytic Ozonation, the conjugated system was completely broken, and thenafter treated by integrated reactor, a part of the carbonyl compound werebroken，and at last after treated by disinfectant pool，almost all the carbonyl compound were broken and change to colorless or litter color material. So,the chrominance of vitamin C wastewater has got a large degree removeeffect.